Delivery valves

ABSTRACT

A delivery valve for a fuel injection pumping apparatus includes a body portion which is slidable within a bore between a pair of abutments. The bore forms part of a passage between an injection pump and an injection nozzle and the member is provided with a valve which when the member is moved under the action of fuel into contact with one of the abutments opens to permit flow of fuel from the injection pump to the nozzle. When the flow of fuel from the injection pump ceases the valve closes and the member moves back towards the other abutment under the action of fuel under pressure in the pipe line connecting the injection pump with the nozzle. A predetermined volume of fuel is therefore allowed to flow from the pipe line towards the injection pump.

United States Patent 1191 [11] 3,742,926 Kemp July 3, 1973 DELIVERYVALVES [75] Inventor: Kenneth Albert Walters Kemp, pmfwry Croyle London,England Assrsram Exammer-R1chard J. Sher Attorney-Holman 8:. Stern [73]Assignee: C.A.V. Limited, Birmingham,

' E l d 57 ABSTRACT [22] Flled' 1971 A delivery valve for a fuelinjection pumping apparatus [21] Appl. N0.: 175,510 includes a bodyportion which is slidable within a bore between a pair of abutments. Thebore forms part of a passage between an injection pump and an injection[30] Forelgn Apphcatlmf p'nomy Data nozzle and the member is providedwith a valve which Aug. 27, Great Bl'ltaln n e mbe i 'mo ed de he cti no uel 1 into contact with one of the abutments opens to permit [52]123/139 123/139 137/5122 flow of fuel from the injection pump to thenozzle. 137/5123 When the flow of fuel from the injection pump ceases [5the valve closes d the member moves back towards [5 8] Flam of Search123/139 139 the other abutment under the action of fuel under pres-137/5125 512'3 sure in the pipe line connecting the injection pump withthe nozzle. A predetermined volume of fuel is therefore [5 6] ReferencesC'ted allowed to flow from the pipe line towards the injection UNITEDSTATESPATENTS pump, 2,044,629 6/1936 Parker 137/5123 3,547,148 12 1970Drori 123/139 DP 5 2 D'awmg F'gures DELIVERY VALVES This inventionrelates to delivery valves for use in liquid fuel pumping apparatus, thevalves being of the kind which are disposed in or adjacent the fuelinjection pump and which open during an injection stroke to permit fuelto flow to an associated engine and which then close and allow apredetermined quantity of fuel to flow back towards the pump at the endof the injection stroke.

The object of the invention is to provide such a valve in a simple andconvenient form.

According to the invention a delivery valve of the kind specifiedcomprises in combination, a member slidable within a bore between a pairof abutments, said bore constituting part of the flow passage from theinjection pump to the associated engine, and valve means containedwithin the member and disposed to open when the member has been moved apredetermined amount by the flow of fuel during an injection stroketowards one of said abutments, said valve means opening to allowcontinued flow of fuel during the injection stroke but closing at theend of the injection stroke, the member then moving into contact withthe other abutment thereby allowing a predetermined quantity of fuel toflow back towards the injection pump.

One example of a delivery valve in accordance with the invention willnow be described with reference to the accompanying drawings in whichz.

FIG. 1 is a diagram of an apparatus including the valve, and

FIG. 2 is a view to an enlarged scale of the valve.

With reference to the drawing there is provided a rotary cylindricaldistributor member 1 in which is formed a longitudinally extending bore3. The distributor member is housed in a body 1a and is driven in timedrelationship with the associated engine. At one end the bore 3 definesan abutment 4 and this end of the bore communicates with the pumpingchamber of an injection pump 1b. Located at the other end of the bore 3is a further abutment in the form of a plug 15. Moreover, extending fromthis end of the bore 3 is a delivery passage 14 which extends outwardlyto the periphery of the distributor member and which is arranged toregister in turn and during successive injection strokes of theinjection pump, with a plurality of outlet ports 14a only one of whichis shown, in the body. The outlet ports are connected respectively tothe injection nozzles 14b of the associated engine respectively.

Slidable within the bore 3 is a cylindrical delivery valve body 2.Formed within the body 2 is a spring chamber having a seating 7 definedat one end. Moreover, for co-operation with the seating there isprovided a valve element in the form of a ball 6. The ball is contactedby a spring abutment 9 and the spring abutment 9 locates against one endof a coiled compression spring 8. The other end of the coiledcompression spring is located about a stop 10 which extends from a plug5 serving to close the end of the spring chamber remote from theseating. Adjacent the plug 5 the spring chamber communicates with theperiphery of the cylindrical member 2 by way of short radially disposedpassages 16 and these are in constant communication with an enlargedportion 'of the bore 3 from which extends the delivery passage 14.

Also provided in the cylindrical member 2 is a transverse drilling 11which opens into the spring chamber by way of the seating. Moreover, theend of the cylindrical member 2 adjacent the abutment 4 is of reduceddiameter and defines an annular space 13 which during movement of thecylindrical member as will be described, can be brought intoregistration with a circumferential groove 12 formed in the distributormember and communicating with the transversely extending passage 11.

In use, when the injection stroke of the injection pump lb starts, fuelentering the bore 3 from the injection pump will urge the cylindricalmember 2 against the action of the spring, and fuel will be expelledfrom the opposite end of the bore and will flow to the appropriate fuelinjection nozzle of the associated engine by way of the delivery passage14. After a predetermined movement of the cylindrical member the space13 will be brought into register with the groove 12. When this occursthe fuel pressure acting on the ball 6 is balanced but it remains incontact-with the seating because of the action of the spring, and thecylindrical member will continue to move forwardly until it is halted bythe stop. When this occurs further fuel flowing from the injection pumpwill lift the ball 6 from the seating 7 against the action of thecompression spring 8 and the fuel will flow to the delivery passage 14by way of the spring chamber and the passages 16. At the end of thedelivery of fuel by the injection pump the ball 6 will close onto theseating 7 under the action of the spring. Moreover, under the action offuel under pressure in the pipeline interconnecting the pump and nozzle,the cylindrical member will move towards the abutment 4. During thismotion the delivery passage 14 is still in register with a delivery portand a predetermined quantity of fuel will flow back towards theinjection pump. This flow of fuel will cease when the cylindrical memberstrikes the abutment 4.

I claim:

l. A delivery valve for use in a liquid fuel pumping apparatus forsupplying fuel to an internal combustion engine, the valve beingpositioned between an injection pump forming part of the apparatus andan outlet, the delivery valve comprising in combination, a bore, a pairof abutments at the opposite ends of the bore, a member slidable withinsaid bore between the pair of abutments, said bore constituting part ofthe flow passage between the injection pump and the outlet, valve meanscontained within the member and disposed to open when the member hasbeen moved by the flow of fuel during an injection stroke of theinjection pump into contact with one of said abutments, said valve meansopening to allow continued flow of fuel during the injection stroke butclosing at the end of the injection stroke, co-operating means on themember and bore for preventing the application of fuel pressure from theinjection pump to said valve means until the member has moved apredetermined extent towards said one abutment, the member at the end ofthe injection stroke, then moving into contact with the other abutmentthereby allowing a predetermined quantity of fuel to flow back towardsthe injection pump.

2. A delivery valve as claimed in claim 1 in which said valve meansincludes a seating, and a spring loaded valve element-which co-operateswith said seating, a passage in the member, said valve means serving toprevent flow of fuel through said passage until the member has contactedsaid one abutment.

3. A delivery valve as claimed in claim 2 in which said passage includesa transverse portion opening onto the periphery of the member adjacentthe end thereof adjacent the other abutment, said transverse portioncommunicating with a groove formed in the wall of the bore, said memberbeing of reduced diameter at the end thereof adjacent said otherabutment, the arrangement being such that as the member moves intocontact with the one abutment the transverse portion is placed incommunication with the bore adjacent said other abutment.

4. A liquid fuel injection pumping apparatus including an injection pumpfor supplying fuel to an injection nozzle and a delivery valve disposedadjacent the fuel injection pump, the delivery valve comprising a bore,a valve member slidable within the bore, a pair of abutments at oppositeends of the bore, an inlet from the injection pump communicating withone end of the bore,

an outlet to the nozzle at the other end of the bore, a transversepassage in the valve member, co-operating means on the valve member andthe wall of the bore whereby said transverse passage is brought intocommunication with said inlet only when the valve member has moved apredetermined amount towards the other end of the bore under the actionof fuel under pressure delivered by the injection pump, a furtherpassage in the valve member communicating with said passage means andsaid outlet, a seating in said passage and a spring loaded valve elementfor co-operation with said seating, said valve element being lifted fromits seating when the member contacts the abutment at the other end ofthe bore.

5. A liquid fuel injection pumping apparatus as claimed in Claim 4 inwhich said co-operating means comprises a groove in the wall of the boreand a reduced portion on the member adjacent said one end of the bore.

1. A delivery valve for use in a liquid fuel pumping apparatus forsupplying fuel to an internal combustion engine, the valve beingpositioned between an injection pump forming part of the apparatus andan outlet, the delivery valve comprising in combination, a bore, a pairof abutments at the opposite ends of the bore, a member slidable withinsaid bore between the pair of abutments, said bore constituting part ofthe flow passage between the injection pump and the outlet, valve meanscontained within the member and disposed to open when the member hasbeen moved by the flow of fuel during an injection stroke of theinjection pump into contact with one of said abutments, said valve meansopening to allow continued flow of fuel during the injection stroke butclosing at the end of the injection stroke, co-operating means on themember and bore for preventing the application of fuel pressure from theinjection pump to said valve means until the member has moved apredetermined extent towards said one abutment, the member at the end ofthe injection stroke, then moving into contact with the other abutmentthereby allowing a predetermined quantity of fuel to flow back towardsthe injection pump.
 2. A delivery valve as claimed in claim 1 in whichsaid valve means includes a seating, and a spring loaded valve elementwhich co-operates with said seating, a passage in the member, said valvemeans serving to prevent flow of fuel through said passage until themember has contacted said one abutment. Pg,8
 3. A delivery valve asclaimed in claim 2 in which said passage includes a transverse portionopening onto the periphery of the member adjacent the end thereofadjacent the other abutment, said transverse portion communicating witha groove formed in the wall of the bore, said member being of reduceddiameter at the end thereof adjacent said other abutment, thearrangement being such that as the member moves into contact with theone abutment the transverse portion is placed in communication with thebore adjacent said other abutment.
 4. A liquid fuel injection pumpingapparatus including an injection pump for supplying fuel to an injectionnozzle and a delivery valve disposed adjacent the fuel injection pump,the delivery valve comprising a bore, a valve member slidable within thebore, a pair of abutments at opposite ends of the bore, an inlet fromthe injection pump communicating with one end of the bore, an outlet tothe nozzle at the other end of the bore, a transverse passage in thevalve member, co-operating means on the valve member and the wall of thebore whereby said transverse passage is brought into communication withsaid inlet only when the valve member has moved a predetermined amounttowards the other end of the bore under the action of fuel underpressure delivered by the injection pump, a further passage in the valvemember communicating with said passage means and said outlet, a seatingin said passage and a spring loaded valve element for co-operation withsaid seating, said valve element being lifted from its seating when themember contacts the abutment at the other end of the bore.
 5. A liquidfuel injection pumping apparatus as claimed in Claim 4 in which saidco-operating means comprises a groove in the wall of the bore and areduced portion on the member adjacent said one end of the bore.